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OpenTrials
Completed

NCT Number: NCT07026500

Clinical Trial for Batch Consistency of EV71 Vaccine

This trial is designed as a single-center, randomized, double-blind study. A total of 720 infants aged 6 to 35 months are selected (with 240 subjects in each age group: 6-11 months, 12-23 months, and 24-35 months). Subjects from different age groups are randomly allocated to three batch groups in a 1:1:1 ratio, and receive two doses of the EV71 vaccine from the commercial production batch on days 0 and 30. After each vaccination dose, subjects will be observed for immediate reactions for 30 minutes and for solicited adverse events for the next 7 days, as well as for unsolicited adverse events over the 30 days following vaccination. All subjects will have blood samples collected on day 0 (pre-immunization) and day 60 for serum antibody testing. Additionally, 270 subjects will be selected, for additional blood sampling at various time points: 7 days, 14 days, and 30 days after the first dose, and 7 days and 14 days after the second dose, to assess the EV71 antibody levels at different timepoints following various doses of vaccination.

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Key information

Conditions

EV71 Vaccine

Age range

6 month–35 month

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

Primary location

Dazhu County Center for Disease Control and Prevention

Dazhu, China

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Infants and young children aged 6 to 35 months.
  • Able to provide legal identification.
  • The guardian of the subject has the ability to understand and agrees to sign the informed consent form.

Exclusion criteria

  • Previous vaccination with the EV71 vaccine.
  • History of hand, foot, and mouth disease.
  • History of allergies, asthma, including allergies to vaccines or vaccine components, and severe adverse reactions to vaccines, such as urticaria, difficulty breathing, angioedema, or abdominal pain.
  • Congenital malformations or developmental disorders, genetic defects, severe malnutrition, etc.
  • Autoimmune diseases or immune deficiencies/immunosuppression.
  • Severe neurological disorders (epilepsy, convulsions, or seizures) or mental illness.
  • History of thyroidectomy, asplenia, functional asplenia, or any condition leading to asplenia or splenectomy.
  • Blood coagulation abnormalities diagnosed by a physician (such as clotting factor deficiencies, coagulopathies, platelet abnormalities) or evident bruising or bleeding disorders.
  • Treatment with immunosuppressants, cytotoxic therapy, or inhaled corticosteroids within 6 months prior to enrollment (excluding corticosteroid nasal spray therapy for allergic rhinitis, or topical corticosteroid treatment for acute non-complicated dermatitis).
  • Receipt of blood products within 3 months prior to vaccination with the trial vaccine.
  • Receipt of other investigational vaccines within 30 days prior to vaccination with the trial vaccine.
  • Receipt of live attenuated vaccines within 14 days prior to vaccination with the trial vaccine.
  • Receipt of subunit or inactivated vaccines within 7 days prior to vaccination with the trial vaccine.
  • Any acute illness or acute exacerbation of chronic illness within the past 7 days.
  • Fever before receiving the investigational vaccine, with an axillary temperature > 37.0°C.
  • Any other factors that, in the investigator's judgment, make the subject unsuitable for participation in the clinical trial.

Treatment and study plan

EV71 vaccine

Biological

EV71 vaccine of commercial production batch

Primary outcomes

  1. The GMT of EV71 neutralizing antibodies 30 days after complete immunization with the EV71 vaccine

    Time frame: 30 days after second dose

Secondary outcomes

  1. Seroconversion rates, seropositive rates, and GMT of antibodies at 7 days, 14 days, and 30 days after the first dose of the EV71 vaccine

    Time frame: 7,14 and 30 days after the first dose

  2. Seroconversion rates, seropositive rates, and GMT of antibodies at 7 days and 14 days after the second dose of the EV71 vaccine, as well as the seroconversion rate and seropositive rate at 30 days post-vaccination

    Time frame: 7,14 and 30 days after the second dose

  3. The incidence of adverse reactions within 30 days after each dose of the EV71 vaccine

    Time frame: 30 days after each dose

  4. The incidence of solicited adverse events within 0-7 days after each dose of the EV71 vaccine

    Time frame: 7 days after each dose

  5. The incidence of serious adverse events during the safety observation period

    Time frame: 30 days after the second dose

Sponsors and collaborators

Lead sponsor

Sinovac Biotech Co., Ltd

Industry

Registry information

Official study title

A Single-center, Randomized, Double-blind Clinical Trial to Evaluate the Safety and Batch Consistency of the EV71 Vaccine in Infants Aged 6 to 35 Months After Vaccination According to a Two-dose Immunization Schedule

Important dates

Study start
2019
Primary completion
2020
Study completion
2020
First posted
Jun 18, 2025
Registry last updated
Jun 18, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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